Magical Plushie Trouble

I've tried using a magical plushie on a mutant pet of mine a couple of times but it hasn't transformed them. Do they not work on mutant pets, do they only have a chance of working, or is there some other problem?

After using the plushie to play with them I'm given one of the regular messages pets give after playing with a toy (Examplepet says 'This is great... buy me more toys!') and the magical plushie is still in my inventory.

It's a Magical Pirate Krawk Plushie, a bit too expensive to lend out. I've been trying to use it on a Mutant Krawk.

I decided to open up a ticket with Neopets about this because there doesn't seem to be a reason why it shouldn't work.

Edit: Update for those that are curious. The ticket didn't accomplish anything, they weren't able to recreate my problem and couldn't offer any more assistance. I decided to paint my pet a different color first (I used a Green Paint Brush due to its relatively low price) to see if that would make a difference, but the plushie still didn't work. My guess is there is just something buggy with my pet. Rather than trying to continue to deal with this I opted to use a Pirate Paint Brush instead.